Integrated Pest Management Program Department of Plant Science and Landscape Architecture UConn Extension

Transcription

1 Integrated Pest Management Program Department of Plant Science and Landscape Architecture UConn Extension Tales from the Field, April 13, 2018 Leanne Pundt, Extension Educator, UConn Extension Highlights of what I have been seeing: Broad mite damage to New Guinea impatiens and Sun impatiens Leaf distortions on New Guinea impatiens Cyclamen mites on delphinium Aphids, a few spider mites (Ipomoea) Greenhouses packed fill of plant material Broad mite damage to New Guinea Impatiens With their piercing mouthparts, broad mites feed on the epidermis of young leaves, causing leaf-margins to curl downward. Broad mites inject a toxin as they feed. This feeding causes twisted, hardened and distorted growth on the plant terminals and bronzed, roughened leaf undersides. Young terminal buds can be killed and leaf edges turn downward. Figure 1: Broad mite damage to New Guinea Impatiens. Photo by L. Pundt

2 Figure 2: Healthy Sun patiens on the left, broad mite damaged plant on the right. Photo by L. Pundt Figure 3: Leaf edges are curling upward. No broad mites were detected. Photo by L. Pundt

3 Regular inspection of crops for broad mite feeding damage is the best way to detect infestations. Besides New Guinea impatiens, other favorite hosts include begonia, dahlia, fuchsia, gerbera daisy, English ivy, lysimachia, salvia, snapdragon, verbena, vegetative petunia, peppers, thunbergia, and wishbone flower (torenia). Often, I see damage symptoms in the same greenhouse locations. If you see characteristic symptoms, inspect leaves under a dissecting microscope or submit samples to me or to a diagnostic laboratory. Broad mite eggs are covered by small whitish bumps that look like a row of diamonds. Figure 4: Broad mite eggs viewed under the microscope. Photo by L. Pundt

4 Cyclamen mite eggs are elliptical and smooth and about half the size of an adult female cyclamen mite. Figure 5: Cyclamen mite egg. Photo by J. Allen Not all miticides labeled for spider mites are labeled for broad mites. Translaminar miticides such as abamectin (Avid or generic abamectin), spiromesifen (Savate) and chlorfenapyr (Pylon) tend to be more effective than contact miticides, especially if leaf canopies are dense or coverage on the undersides of leaves is difficult. Note: Be sure to follow label precautions for crop safety! The Savate (spiromesifen) label recommends not spraying impatiens species (including New Guinea impatiens). Dr. Sarah Jandricic, Floriculture IPM Specialist, OMAFRA, Vineland reports that she has seen high levels of Amblyseius cucumeris applied weekly as a broadcast application, suppress broad mites. For more: The Pest from Abroad: Watch for Broad Mites on Spring Crops:

5 Rippling on New Guinea Impatiens Leaves Figure 6: New Guinea impatiens. Photo by L. Pundt This rippling of the leaves may be signs of high salts. Keep checking your ph and EC levels! Please read the pesticide label prior to use. Trade names used herein are for convenience only; no endorsement of products is intended, nor is criticism of unnamed products implied. Disclaimer for Fact Sheets: The information in this document is for educational purposes only. The recommendations contained are based on the best available knowledge at the time of publication. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. UConn Extension does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available. The University of Connecticut, UConn Extension, College of Agriculture, Health and Natural Resources is an equal opportunity program provider and employer.